A hitherto known luminaire has used various types of illuminating light sources, such as a fluorescent lamp, an incandescent lamp and a spot light, but there have been many limitations on its installation due to its illuminating light containing an ultraviolet component inducing a deterioration of an illuminated subject and to a heat generation of the illuminating light sources. Recently, since an LED light source having less heat generation and power consumption has attracted more attention, and a white LED having a high luminance has also been provided, there is an increasing number of luminaires for general lighting using the LED light source. An example of this kind of illuminating device is disclosed in, for example, Patent Document 1.
Also, to date, in a case of an illuminating device, in order to obtain a desired illuminance, individual luminaries have been disposed on a ceiling or the like at prescribed spaced intervals. Consequently, an operation to previously determine an attachment position of each luminaire has been carried out at an illuminating device installation site.
Patent Document 1: JP-A-2000-021209